1. Field of the Invention
The present invention relates to a projection-type image display apparatus that performs color-separation of light from a light source.
2. Description of the Related Art
In the past, projection-type image display apparatuses (liquid crystal projectors) displaying image in various ways have been proposed. US 2009/0237616 discusses a configuration that uses a polarizing ray splitter and a cross dichroic prism to separate light from a light source into lights of a plurality of wavelength bands and irradiate reflection-type image display elements (light modulation elements) corresponding to the lights of the respective wavelength bands with the separated lights. The lights with which the reflection-type image display elements are irradiated are reflected with their polarization states changed according to an image signal and are then projected onto a screen through the cross dichroic prism and the polarizing beam splitter and.
In order to suppress the degradation of a contrast of a projection image by a phase difference caused by a dichroic film of the cross dichroic prism, US 2009/0237616 designs the dichroic film such that the phase difference caused by the dichroic film is 15 degrees or less.
However, the dichroic film of US 2009/0237616 has a problem in that the color separation characteristics of the dichroic film are degraded.